While vacationing in London, Richard Hannay (played by Robert Donat) befriends a scared woman (Lucie Mannheim) who, in the course of an evening, tells him that she is actually a spy and makes a cryptic reference to “the 39 steps.” The woman is later murdered, and Hannay becomes the prime suspect. He flees on a train to Scotland, and while on board he meets Pamela (Madeleine Carroll), an attractive young woman who tries to have him arrested. Hannay manages to escape, but he later goes to the local police to tell his story. They do not believe him, however, and Hannay runs. Soon thereafter he is spotted by Pamela, who alerts the police. Hannay is arrested, and Pamela is asked to accompany the officers. However, when it becomes clear that the men are not police officers, Hannay manages to escape once again, this time handcuffed to Pamela. The two make their way to a boardinghouse in the countryside, where Pamela slips out of the handcuffs while Hannay is asleep. As she is about to leave, Pamela overhears a conversation which convinces her that Hannay’s incredible stories are true and leads her to stay with him. The action climaxes at the Palladium in London, where Hannay finally deduces the secret of “the 39 steps.” With a performance taking place on stage, Hannay is able to expose the spy ring and finally prove his innocence.

Although Hitchcock had already made a string of successful movies, The 39 Steps brought him international recognition and helped launch his Hollywood career. The thriller, based on a 1915 novel by John Buchan, also became a defining film in Hitchcock’s career. Notably, The 39 Steps centres on what became one of his most commonly used themes: an innocent man is mistakenly accused of a crime and must clear his name. In addition, the movie highlighted the director’s ability to combine taut suspense with humour.